The present invention relates to an edging restraint system for maintaining segmented paving units within a predetermined boundary.
In recent years, there has been an increasing use of segmented paving units such as paving stones and paving bricks for forming sidewalks, driveways, industrial and commercial pavements, and road surfaces. Due to the large variation in color and shape configurations available with paving stones and the like, coupled with their extremely hard traffic bearing characteristics, the use of such paving stones is quite advantageous with respect to the variations and flexibility that one can apply in landscaping projects and the like.
My U.S. Pat. No. 4,863,307, issued Sept. 5, 1989, relates to a paving stone restraint system which has met with substantial commercial acceptance due to its simplicity of construction and reliability and simplicity of installation to hold segmented paving units, such as paving stones and paving bricks in place. The present invention is directed toward improving on this restraint system, and more particularly on providing for a more rugged and durable restraint system for use in industrial/commercial settings where extremely high forces are applied to the paving surfaces and edge restraint members. The present invention is also directed toward improving side force resistance characteristics of the restraint system. Throughout this specification, preferred embodiments for restraining paving stones are described. It will be understood by those skilled in the art that many aspects of the restraint systems can also be applied to restrain other segmented paving units, such as paving bricks, paving blocks of wood, and the like.
According to especially preferred embodiments of the present invention, an edging system is provided which includes a vertical strip which has a side surface that faces and restrains the paving stones and a horizontal base which is connected to the vertical strip to hold the same in position. The horizontal base of preferred embodiments of the present invention includes a paving stone supporting extension which protrudes substantially under the paving stones, such that vertical forces acting on the paving stones are transmitted via the sand or other paving stone bedding to clamp this paving stone support extension against lateral outward movement.
In certain preferred embodiments, the horizontal base also extends laterally outward of the vertical restraint surface which engages the paving stones and is anchored in position in the soil/base by means of anchoring spikes. In certain preferred embodiment, holes can be provided in the horizontal base support surface at both the outwardly protruding portion and at the inwardly protruding stone supporting portion, thereby providing for a very firm, strong anchoring of the restraint edge system.
In especially preferred embodiments, the vertical strip and the horizontal base are connected together as a unitary extruded plastic piece. This extruded plastic configuration has a constant cross section so that indeterminate lengths can be economically extruded, the same being then cut to length as desired to accommodate shipment and installation. Since one needs only to drill holes for the anchoring spikes to have a ready to use restraint system that can be easily transported to the paving stone installation site, this type of configuration is very practical and economical.
Other preferred embodiments are contemplated which are manufactured by other manufacturing processes such as blow molding of plastic and injection molding of plastic. These processes allow for variation in the cross-section along the length of the restraint system to accommodate savings of plastic and to accommodate special shape configurations that vary along the system length.
In order to even further enhance the resistance of the restraint edge system to lateral movements, certain preferred embodiments include ribs or other gripping protrusions at the bottom of the horizontal base for biting into the underlying soil/base to further prevent side slippage in the event of lateral forces on the paving stones. In especially advantageous embodiments where the vertical restraint and the horizontal base are extruded together, these protrusions are also extruded as longitudinally extending ribs of the restraint edge. Thus, a restraint system is obtained in a simple manner which is very firmly anchorable in position, with the (i) gripping protrusions, (ii) the spikes and (iii) the paving stone underlying support extension all serving separately and also cooperating to provide for a very reliable firm maintenance of the paving stones in position, even in the event of extremely large industrial vehicles travelling along the boundary edges of the paving surface comprised of paving stones.
In certain preferred embodiments, the anchoring spike holes in the paving stone underlying extension are offset in the longitudinal direction of the restraint edge with respect to the anchoring spike holes in the outwardly protruding horizontal base section, thereby providing for a reliable anchoring, without unduly weakening the plastic restraint edge system. This offset arrangement enhances the anchoring effect of the spikes by providing multidirectional anchoring resistance forces from a plurality of spikes during use with vehicle traveling loads moving along the edge of the paving surface.
In certain preferred embodiments, the restraint edging system includes reinforcing connections between the vertical restraining and the outwardly protruding horizontal base portion, thereby further strengthening the restraint edge system. In certain preferred embodiments, the reinforcing is also formed as a continuous longitudinal extrusion s that the complete restraining edge strip can be made as a single continuous piece by simple extrusion molding operations.
In certain preferred embodiments, reinforcing fillets are provided at the inside corner between the vertical restraining portion and the horizontal stone support portion. Such reinforcing fillets are especially advantageous in embodiments which do not have an outwardly extending base section.
In other preferred embodiments formed by other manufacturing processes, such as injection or blow molding processes, the reinforcing is in the form of discrete reinforcements spaced along the length of the restraint system.
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawings.